Exhaust aftertreatment systems receive and treat exhaust gas generated from an internal combustion (IC) engine. Typical exhaust aftertreatment systems include any of various components configured to reduce the level of harmful exhaust emissions present in the exhaust gas. For example, some exhaust aftertreatment systems for IC engines, such as diesel-powered IC engines, include various components, such as a diesel oxidation catalyst (DOC), particulate matter filter or diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst, among others. In some exhaust aftertreatment systems, exhaust gas first passes through the diesel oxidation catalyst, then passes through the diesel particulate filter, and subsequently passes through the SCR catalyst.
Each of the DOC, DPF, and SCR catalyst components is configured to perform a particular exhaust emissions treatment operation on the exhaust gas passing through the components. Generally, the DOC reduces the amount of carbon monoxide and hydrocarbons present in the exhaust gas via oxidation techniques. The DPF filters harmful diesel particulate matter and soot present in the exhaust gas. Finally, the SCR catalyst reduces the amount of nitrogen oxides (NOx) present in the exhaust gas.
One or more exhaust aftertreatment components, such as the DOC, DPF, and SCR catalyst can be housed in a common housing in an end-to-end or end-to-side configuration. Exhaust aftertreatment components may be controlled based on detected operating conditions to facilitate optimal exhaust emissions treatment. Typically, the operating conditions include exhaust gas conditions that are detected by one or more sensors in fluid communication with the exhaust gas passing through the exhaust aftertreatment system. The sensors may be electrically coupled to one or more modules that process and transmit data associated with the signals received from the sensors. For example, a conventional exhaust aftertreatment system may include exhaust temperature sensors to detect the temperature of exhaust gas at various locations within the system, exhaust pressure sensors to detect the pressure of exhaust gas at various locations within the system, NOx sensors to detect the concentration of NOx in the exhaust gas at various locations within the system, and ammonia (NH3) sensors to detect the concentration of ammonia in the exhaust gas at various locations within the system. The sensors and associated modules are commonly mounted onto an exterior of the housing that contains the exhaust aftertreatment components.
Conventional aftertreatment component sensors and modules are susceptible to degradation and failure due to exposure to excessive heat and vibration. Heat from the exhaust gas flowing through the exhaust aftertreatment components tends to transfer from the exhaust gas, through the housing, and into the sensors and modules via conduction and convention. Further, the sensors and modules may vibrate during operation of the engine due to vibrations induced by the engine and/or by a vehicle in which the engine is housed. Although some heat transfer and/or vibrations may be tolerable, excessive heat transfer and/or vibrations may result in fault codes, vehicle down time, and higher costs.